To find the concentration of the unknown phosphoric acid solution, we first need to write and balance the chemical equation for the reaction between phosphoric acid (H3PO4) and sodium hydroxide (NaOH). The balanced equation is as follows:
H3PO4 + 3 NaOH → Na3PO4 + 3 H2O
Now, we can use the stoichiometry of the balanced equation and the given titration data to calculate the concentration of the phosphoric acid solution.
Given data:
Volume of phosphoric acid solution (H3PO4) = 5.00 mL
Volume of sodium hydroxide solution (NaOH) used for titration = 6.55 mL
Molarity of sodium hydroxide solution (NaOH) = 0.1003 M
Since the balanced equation shows a 1:3 ratio between H3PO4 and NaOH, we can set up the following proportion:
(5.00 mL H3PO4) / (6.55 mL NaOH) = (Unknown concentration of H3PO4) / (0.1003 M NaOH)
Solving for the unknown concentration of H3PO4:
(Unknown concentration of H3PO4) = (5.00 mL H3PO4) * (0.1003 M NaOH) / (6.55 mL NaOH)
(Unknown concentration of H3PO4) = 0.0762 M
The concentration of the unknown phosphoric acid solution is approximately 0.0762 M.
Hope this helps.
willkiddhill